Prepare a large skillet.

Butter the outside of each piece of bread with about one teaspoon and place both pieces butter side down in the skillet. On the first piece, cover the top with the pesto followed by 1 slice of cheese and the sliced turkey. Top the second piece with the other slice of cheese.

Cover and cook on medium low heat until the bread is lightly browned and cheese is mostly melted, about 5 minutes.

Top the turkey with the spinach and sliced tomato and using a spatula, place the second piece of bread and cheese on top. Cook for 1 additional minute until the cheese is completely melted and the spinach is just starting to wilt.

Serve immediately.